Widely developed in the Dabie complex are various disequilibrium textures whichprovide direct evidence for the evolution of metamorphism and late-stage uplifting history. Thetypical mineral assemblage in the Opx-Gt Pl...Widely developed in the Dabie complex are various disequilibrium textures whichprovide direct evidence for the evolution of metamorphism and late-stage uplifting history. Thetypical mineral assemblage in the Opx-Gt Pl-Bi gneiss in Huangtuling, Luotian County, HubeiProvince, is Opx(I ) + Gt + Pl(I ) + Bi(I ) + Q. The corona composed of cordierite and orthopyroxene (Ⅱ) growing around garnets in the granulite makes it clear that there occurredthe following metamorphic reaction: Gt + Q→Cd + Opx(Ⅱ). It is estimated that the granulite-forming temperature (T ) and pressure (P ) are 857 - 998° and 1. 18 - 1. 23 GPa, respectively, and the corona was formed under the following conditions: T = 829 - 911℃ and P= 0. 53-0. 59 GPa. The above results indicate that there occurred a rapid and nearly adiabaticuplifting event and a decompressional metamorphism in the Dabie complex after the formationof granulite. As compared with the granulites worldwidely distributed in 90 locations (Harley,1989), the Huangtuling granulite should belong to the high-pressure type, which representsthe composition of the crust at a depth of more than 40 kilometers.展开更多
文摘Widely developed in the Dabie complex are various disequilibrium textures whichprovide direct evidence for the evolution of metamorphism and late-stage uplifting history. Thetypical mineral assemblage in the Opx-Gt Pl-Bi gneiss in Huangtuling, Luotian County, HubeiProvince, is Opx(I ) + Gt + Pl(I ) + Bi(I ) + Q. The corona composed of cordierite and orthopyroxene (Ⅱ) growing around garnets in the granulite makes it clear that there occurredthe following metamorphic reaction: Gt + Q→Cd + Opx(Ⅱ). It is estimated that the granulite-forming temperature (T ) and pressure (P ) are 857 - 998° and 1. 18 - 1. 23 GPa, respectively, and the corona was formed under the following conditions: T = 829 - 911℃ and P= 0. 53-0. 59 GPa. The above results indicate that there occurred a rapid and nearly adiabaticuplifting event and a decompressional metamorphism in the Dabie complex after the formationof granulite. As compared with the granulites worldwidely distributed in 90 locations (Harley,1989), the Huangtuling granulite should belong to the high-pressure type, which representsthe composition of the crust at a depth of more than 40 kilometers.
